Handle construction for hammers and similar impact tools



C. M. LAY

May 9, 1961 HANDLE CONSTRUCTION FOR HAMMER-S AND SIMILAR IMPACT TOOLS Original Filed Aug. 23, 1957 INVENTOR: CLARENCE M. LAY

ATT'Y United. States Patent HANDLE CONSTRUCTION FOR HAMNIERS AND SIIVIILAR IMPACT TOOLS Clarence M. Lay, Bushnell, 111., asiguor to Vaughan & Bushnell Mfg. Co., Bushnell, 111., a corporation of Illinois Original application Aug. 23, 1957, Ser. No. 679,833, now Patent No. 2,884,969, dated May 5, 1959. Divided and this application Sept. 20, 1957, Ser. No. 685,187

1 Claim. (Cl. 14529) The present invention relates to portable impact tools and has particular reference to a handle construction for such tools. The invention has been illustrated and described herein in connection with the formation of carpenters claw hammer of the type shown and described in my co-pending application Serial No. 679,833, filed August 23, 1957, now Patent No. 2,884,969, for a Hammer Construction and Method of Forming the Same, of which application the present application is a division. The invention may, however, find use in connection with other impact tools, as for example machinists hammers, blacksmiths hammers, bricklayers hammers and similar tools. construction and formation of impact tools of the socalled indestructible type having steel shanks which are integral with the striking heads of the tools.

The invention is specifically concerned with the In recent years there have appeared on the market 7 claw hammers in which the handles or shanks are formed of steel and are integral with the hammer heads, such hammers to a limited extent supplanting or more aptly supplementing the widely known and used hickory handle claw hammer. These indestructible hammers, as currently constructed, offer a few advantages over conventional wooden handle hammers but they are also possessed of numerous limitations. Chief among the ad vantages afforded are increased strength and a permanent union between the hammer head and shank. Whereas, in the case of a wooden handle hammer having an impact head fornail-driving purposes with integral claws for nail-pulling purposes, the hammer will ordinarily withstandeven the roughest usage when put. to the use for which itl is intended, the wooden hammer handle,

when used'for unintended purposes, as for example 1 wrecking, will frequently break or come loose. Such is not the case with so-called indestructible hammers having integral steel shanks. Similarly, a wooden hamrner handle will, in'tirne, dry out and'become subject to looseness, splitting, orto shearing forces at its region of juncture with the impact head while, obviously, such limitations are not attendant upon the use of integral steel hammepshanks; These factors, together with the fact that indestructible type hammers possess design possibilities whereby they may be made in a variety of attractive styles possessing eye-appeal, are ascribed as possible reasons why such hammers have met with a modicum of success on the market.

On the other hand, indestructible hammers of the type brieflyputlined above and as presently manufactured are possessed of numerous limitations, principal among which are lack of resiliency which renders them awkward in the hands of an experienced carpenter or workman; the tendency for impact to set up undesired harmonic vibrations; theinability under prevalent manufacturing processes to produce a hammer assembly of correct oraccepted proportions; and the large number of operations which are required to produce the combined head, claw and shank unit of the hammer assembly.

Due to the greater density and weight of steel-as Patented May 9, 1951 compared to wood, these solid steel indestructible types of hammers are not balanced properly, which is to say that they are handle-heavy and cannot successfully be subjected to the usual tests for proper balance. The art of constructing hammers, particularly carpenters claw hammers is an exacting one. In few other arts does such a little difference make such a big difference. It is truly an art of tremendous trifles. The term balance is not readily definable, but it may be stated that a properly balanced hammer, particularly a carpenters claw hammer, is one which in the hands of an experienced carpenter gives him a sense of satisfaction and confidence in his manipulation of the tool. It is one which is easily aimed and will find impact squarely at the desired point of impact. A hammer which is not properly balanced feels awkward or heavy in the hand of the experienced user and in swinging the same, centrifugal and other forces are set up which give an unnatural feeling to the user just as does an improperly balanced golf club or tennis racket to the expert. One test for proper balance commonly employed by prospective purchasers of conventional sixteen ounce hammers is to place the hammer head down, on a fiat level surface, allowing the weight of the hammer to be borne on the curved surface of the claws near the base thereof so that the hammer assumes a rocking position on this curved surface with the handle extending upwards at an acute angle with respect to the flat supporting surface. Then, if the hammer is capable of assuming a stable degree'of equilibrium, this is an indication of proper hammer balance. On the other hand, if the hammer cannot be thus supported and instead it possesses an unstable degree of equilibrium, th sis an indication that the hammer is not properly balanced. So far as is known, present day solid head and shank indestructible hammers are incapable of passing such a test.

Present day indestructible hammers of the type briefly outlined above will vibrate after impact, the vibration being accentuated in the claw region of the hammer. Not only is such vibration unpleasant to the sense of touch but repeated vibration rover along period of time setsup stresses in the body of the hammerin the vicinity of the claw which, in time weakens the metal in this region so that upon a subsequent occasion when the claw is used for leverage purposes, one or both claws will break away fromthehead. I

Although hammers are made in various sizes,-and although the proportions of the various constituent parts of a hammer-may vary widely, a standard carpenters claw hammer usually has a 16 ounce head and a handle which is on the order of slightly greater than 13 inches.

The overall longitudinal extent of'the hammer head is in the order of five and one-half inches. Any material deviation from these dimensions or from such weight of the hammer head will not be tolerated by a carpenter. These dimensions and weights are applicable to both wooden handle hammers and to indestructible type hammers. For these reasons, manufacturers of indestructible type hammers make an efIort to maintain the same general size, and shape as between the indestructible type hammer and the conventional wooden handle hammer. However, manufacturing difiiculties arise which have heretofore prevented the indestructible type of hammer from being a substantial replica of the wooden handle hammer insofar as shape and weight are concerned and manufacturers have been obliged to effect a compromise in the proportions of indestructible type hammers. Due to the fact that integral head and shank type hammers are solid and are devoid of the usual hollow eye into which the wooden handle is inserted and in which it is anchored, the additional metal involved if the same shape and dimensions are to be preserved, will lead to the construction of a hammer having a head which is overweight. In other words, a hammer having a solid metal head which Weighs sixteen ounces will not be as large as ahead which is formed with a hollow eye there- 'through for reception therein of the end of the handle.

invention contemplatesthe provision of a novel form of rubber and steel handle assembly providing unusual lightness by virtue of the use ofaminimum uantity of metal in the assembly, together wtih the inclusion of unfilled voids or empty cells within the confines of the assembly. This feature of the invention is carried out by utilizing a forged shank portion which is functionally integral with the head'portion of the hammer, and which shank portion is itself extremely thin and consequently light,- but which nevertheless is of full length, which is to say that it extends substantially to the end of the handle remote fromthe hammer head. This shank portion, although of thin'construction, is strong and lends rigidity to the. handle and has associated therewith a molded rubber grip membernzif one piece construction which completely encloses the shank portion and further contributes to the lightnessof the handle assembly as 'a whole by the inclusion therein of unfilledvoids or empty cells, these cells serving the additional function of lending resilience to the handle when the hammer is in use. Since a'minimum quantity of metal is required in the construction of the shank portion of the forged hammer; the metal which is thereby saved may be applied to the head portion of the hammer to preserve'the correct proportioning rubber grip element having a central longitudinal bore formed therein through which the shank portion extends in such a manner as to divide the bore into two hollow elongated air cells, one on each side of the shank portion, so that a degree of pneumatic resilience is offered to the hand of the user and so that upon long and continned usev of thetool the rubber grip. portion of the handle may tend to assume a configuration conforming to the hand of the. user, thus giving comfort to the hand throughout the life of the tool;

The provision of a handle assembly for indestructible type hammers which lends itself to economy of manufacture and ease of assembly during such manufacture are further desirable features that have been borne in mind'in the production and development of the present invention.

'In the accompanying single sheet of drawing forrrung a part of this specification, a preferred embodiment of and balancing of the hammer as a whole as previously outlined above. By such an arrangement it is possible to construct an indestructible type hammer'having a head portion and a handle portion which more nearly approach the size, shape, and weight of the head and handle portion respectively of a properly pro'por' tioned hickory handle hammer. The provision of a hammer of this sort having a handle assembly of relatively light weight, thereby enablin'g'more metal'to be forged into the head portion of the hammer being among the principal objects of'the invention, another important object is toprovide such a hammer wherein the steel core or shank portion is possessed of maximum strength consistent with minimum mass in that it is'formed generally in the shape of an I-beam having strengthening ribs along its longitudinal edges connected together by an intervening web portion.

Another object of the invention is to provide a handle constructionfor indestructible type hammers in which the rubber'grip portion is telescopically received over the shank portion of the hammer and is so contoured externally that the surface thereof merges uniformly with the contour of the neck portion of the handle, thus re sulting in an overall handle assembly which presents no sharp protuber'ances or other surface irregularities.

Yet another object of the invention, in an indestructible hammer of this type, is to provide a handle assembly a carpenters claw hammer having a handle construction manufactured in accordance with the principles of the present invention hasbeen illustrated.

In this drawing: p v

Fig. l is a side elevational view of a carpenters claw hammer constructed in accordance with. the principles of the present invention and showing the improved hart-- dle construct-ion associated therewith, certain parts of the View being broken 'awayto more clearly reveal the nature of theinvention. 7 7

Fig. 2 is a side elevational view ofthe structure shown in ,Fig. 1, likewise with certain parts-being broken away.

Fig. 3 is a sectional view taken substantially along the line 3-3 of Fig. 1. p

'Fig. 4. is a sectional viewtaken substantially along the line 4-4 of Fig. l.

Fig. .5 is a side elevational view of a shank unit employed in connection with the present invention, and

Fig. 6 is a sectional view taken substantially centrally and longitudinally through a rubber grip element employed in connection with the present invention.

Referring now to the drawings in detail and in particular to Figs. 1 and 2, the handle construction of the present invention is shown as being applied to an impact tool in the form of a carpenters claw hammer of the indestructible type and which, for purposes of discussion herein, is moreor less of. standard dimensions, i.e. it is provided with a'l6 oz. head, a:13"'.shank involving the present handle construction and has a longitudinal spread across the head portion of 5 /2". Such a hammer is generally' acceptable to carpenters and similar tradesmen andthe handle portion thereof is. dimensioned and is of such an overall weight as to best adapt itself to the type of head portion illustrated. It will be understood however, that for other types of hammer head constructions the handle portion may be modified'within the scope of the present invention to best accommodate itself to such heads. 1 i

The hammerhead 'is designated in its entirety at 10 and is integral with the handle shank 12. Thehead 10 in the illustrated form of the invention is'of the bellfaced type and includes a cylindrical impact head proper 14 having a'circular impact surface '16.-The impact head proper 14 is connected-*toone side or the medial body portion 18 by a constricted portion 20 which is verging claws 26. The shank 12merges with the head 10 along gradually formedcurved surfaces 28 as is cusmersr The medial bodyportion lti of-the hammer head 10 'is formed with a relatively deep socket 30 therein which is generally rectangular in cross section asseen in Fig. 1 and the four walls 31 of which converge in-- wardly toward each other in the outer regions ofthe socket. The bottom wall of'the socketis slightly dished ver O as shown at 32 in Fig. 1. The rectangular socket 30 provided in the'inedial body portion 18 of the hammer head may be left exposed so that it assumes the appearance whichit h'as when it emerges from the shaping operation in the manufacture of the head portion of the hammer as seeii'in Fig. 1, but preferably this socket 30 is filled with a vibration dampening substance such as a suitable thermoplastic or thermosetting material as indicated at 33: Alternatively, it may be filled with a hickory plug which, -if desired, may be concealed by an outer veneer of the plastic material.

The shank '12-is comprised of a proximate grip section 34 and a distal connecting section 36 by means of which the grip section is operatively connected to the head 10. The distal section 36 is generally elliptical in transverse cross section, the ellipse having a relatively short minor axis and a relatively long major axis so that this portion of the shank is relatively thin in the transverse direction of the hammer as a whole. The proximate grip section 34 is generally flat and the longitudinal side edges thereof are formed with marginal ribs 38 so that the section is generally H-shape in cross section.

The grip section 34 is adapted to receive thereover a tubular handle proper or grip 40 which is formed of a suitable resilient material such as rubber either natural or synthetic or of a rubber substitute having good shockabsorbing qualities. The grip 40 is formed with a relatively deep socket 42 therein (Fig. 6) and into which the grip portion 34 of the shank 12 may be inserted by telescoping the grip 40 over this portion of the shank during the finm assembly of the hammer. A pair of oppositely disposed T-shaped slots 43 are formed in the wall of the grip to receive the marginal ribs 38 and, when the grip 40 is fully received on the grip portion 34, the web portion of the latter extends across the socket 42 with clearance regions 41 existing between the wall of the grip and the web part of the grip portion.

The marginal ribs 38 have overall dimensions which are slightly greater than the confining dimensions of the T-shaped slot 43 so that when the grip 40 is telescoped over the grip section 34 of the shank there will be a fairly tight frictional engagement between the telescoping parts. The bottom wall 44 of the socket 42 is of appreciable thickness and serves to limit the extent of telescopic reception of the grip 40 over the metal grip section 34. As best seen in Fig. 6, the walls of the socket 42 taper forwardly and inwardly as at 46 and the forward end of the socket terminates in a narrow slot 48 which closely hugs the forward region of the proximate grip section 34, with the extreme end of the grip 40 abutting against a shoulder 50 existing at the juncture between the proximate grip section 34 and the distal connecting section 36. The outer surface of the grip 40 is tapered inwardly as at 52 and merges evenly into the contour of the distal connecting section 36 as best seen in Fig. 1. The grip 40 is maintained in its telescopic relation over the grip section 34 by the strong frictional bond between the rubber and metal parts in the vicinity of the T-shaped slot 43 and ribs 38. However, to insure a permanent union between the parts, a quantity of a suitable adhesive may be applied between the rubber grip and the metal of the grip section 34 in the vicinity of the slot 48 at the time the grip 40 is positioned over the grip section 34, and thereafter, by the application of heat to the grip, a permanent union may be effected by a vulcanization process.

The handle construction described above is possessed of good shock-absorbing qualities, and by virtue of its lightness, it enhances the balance of the hammer construction as a whole. Since the metal grip section 34 is extremely thin, much of the weight of the handle as a whole at the proximate end thereof, i.e. in that portion of the hammer that is gripped by the hand of the user,

is relieved of considerable weight, and thus in the forging process by means of which the metal hammer head 10 and shank portion 12 thereof are formed, as described in 6 my abovementioned copending application, an additional quantity of metal may be forged into the head portion 10 to build up the size of the hammer head to correct proportions for hammers of this In' other words, by the provision of the improved handle construction of the present invention; it is possible to forge a metal hammer head and shank assembly where additional weight is applied to the hammer head 10 where it properly belongs to produce a hammer of given size without decreasing the overall weight or bulk of the hammer construction as a whole.

The web portion of the metal grip section 34 extending between the two marginal ribs 38 divide the longitudinal bore of the socket 42 into the two clearance regions 41 on opposite sides of the web and these clearance regions constitute, in effect, hollow air cells which function pneumatically to give resilience and good shockabsorbing qualities to the grip 40.

In order to enhance the frictional characteristics of the grip 40 in the hand of the user, as well as to lend flexibility to the walls of the grip, and also as a decorative measure, a series of small depressions 60 may be formed exteriorly on the surface of the grip on opposite sides thereof during the molding operation of the grip.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawing or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit of the invention. For example, while the improved handle construction of the present invention has been shown as being applied to a hammer head and shank construction of the type illustrated in my above-mentioned copending application, it will be understood, of course, that the handle construction is applicable to other types of impact tools. Only insofar as the invention has particularly been pointed out in the accompanying claim is the same to be limited.

I claim:

An indestructible type hammer construction comprising in combination a hammer head provided with a steel shank having a distal portion providing a core and, in addition, an intermediate proximate neck portion connecting the distal portion and hammer head, said distal portion being in the form of a relatively thin flat imperforate web of uniform transverse cross section throughout and having longitudinally extending oppositely directed ribs extending along each marginal edge thereof and. projecting out of the plane of the web, a continuous shoulder formed on said steel shank at the juncture between said neck portion and said distal portion and surrounding the extreme proximate end of the web and a one-piece tubular grip formed of molded resilient elastomeric material, received telescopically on and coextensive with the core, and embodying a tubular side wall, said tubular grip being generally elliptical in transverse section throughout, said tubular grip being formed with a central bore across which the web extends in diametrical fashion with the plane of the web coincident with the major elliptical axis of the grip, the web thus dividing the bore into two isolation air pockets on opposite sides of the web respectively, the side wall portions of said grip in the'vicinity of the ends of the major elliptical axis being relatively thick and incompressible throughout the longitudinal extent of the grip and being formed with internal T-shaped slots at diametrically spaced regions, the ribbed edges of said web fitting into said T-shaped slots respectively, the side wall portions of said grip in the vicinity of the ends of the minor elliptical axis being relatively thick in the proximate regions of the grip, tapering in thickness toward the distal end of the grip, and being of such mean thickness that they are capable of slight compression and inward deflection when the grip is properly gripped by the user in connection with normal use of the hammer construction, said tubular grip being formed with an integral imperforate end wall completely closing the distal end of the grip, the

grip, said end wall being formed with an internal socket having a cross sectional shape, conforming to the transverse cross sectional shape of the shank, thus providing a thin medial region with enlarged voids at the opposite ends thereof respectively, the distal end region of said shank extending into and substantially filling said socket withsaid web filling s a-id thin medial region and said ribs filling said enlarged voids and with the extreme distal end of the shank abutting against the bottom of the socket, said grip having its proximate end region closely hugging the proximate end region of the core whereby said air pockets are each hermetically sealed.

References Cited in the file of this patent w /',UNITED STATES PATENTS p 445,914 Waterson Feb.,3, 1891;

476,424 Smith June-7, 1892. 1,581,647 Layton Apr. 20, 1926 1,707,787 Estwing Apr. 2, 1929 2,618,986 Hungerford Nov. 2.5, 1952 2,754,863 Yearley July 17, 1956 

